Changes that improve database performance.
SAP IQ leverages information available in a hash-partitioned or a hash-range-partitioned table to improve the performance of some equality conditions on the hash-partitioning basis column.
<column> = constant-expression
That <column> is a base column in a real table, not from a view or a derived table.
The base column is the sole basis for the hash partitioning of the table containing that <column>.
That constant-expression is either a literal constant, a host variable, or a simple scalar expression containing only constants and host variables, not a scalar subquery or an aggregate expression.
The equality condition is in the SQL statement at a location which allows it to be applied at the leaf node in the query plan, not in some other query block, and not in a ON clause of FULL OUTER JOIN in the same query block.
The datatype of the constant-expression is highly compatible with the datatype of the base column.
HashPartitionNumber( <column> ) = integer-constant
Performance and Tuning > Schema Design > Hash Partitioning
In SAP IQ 16.0, a redesign in memory usage reduced memory footprint and provided better parallel processing for loads. As a result, the row log file for LOAD TABLE IGNORE CONSTRAINT now returns NULL strings instead of the original file contents for certain values when data conversion errors occur.
LOAD TABLE dbo.IQ_TEST ( amount ASCII(10) null(ZEROS), FILLER ('\n') ) FROM 'c:\data\test.data' quotes off escapes off format 'ascii' strip off with checkpoint off ignore constraint DATA VALUE 50 message Log 'c:\log\test.log' row log 'c:\log\test.row' only log ALL
100.4 ABCED 265.3456 23.4 . 234 345
SAP IQ 15.4 returns these rows:
2 ,ABCED , 5 , . ,
1 ,NULL, 2 ,NULL,
Cases such as column check constraints continue to generate the correct rows.
SAP IQ now fully parallelizes and distributes UNION ALL operators on a cost basis, along with other data flow operators, regardless of the number of unions, union arms, or operator types. You will see significant performance increases over previous releases, on the same hardware, without tuning or schema changes. This improvement particularly benefits DAS configurations. Unions are even partially parallelized if some arms do not allow parallelism or are not worth parallelizing on a cost basis.
Queries combine similar data from multiple locations, often a small work table and a larger historical table. Queries typically select data from all tables.
Identical tables store a similar size period of data. Queries typically select data from specific periods.
SAP IQ now opens all UFS (Unix File System) database files using direct I/O.